The present invention relates to pile weatherstripping and more particularly to a pile weatherstrip which is formed by bending and insertion of a strip of side-by-side strands of flat pile into a kerf or other slot in a member for providing sealing action along a surface of the member through which the pile extends.
It is a feature of the present invention to provide pile weatherstripping which is formed from flat pile. Another feature of the invention is to provide pile weatherstripping which is operable in compression or in a bending mode. In the bending mode, the pile can bend over a range covering different size clearances between members to be sealed. A single size of flat pile can form weatherstripping which covers a large range which may be approximately 100 mils (0.100 inch) of clearance, or more. Still another feature of the invention is to provide weatherstripping which may be manufacturable at lower cost than weatherstripping which has been heretofore available, such as of the type shown in Johnson, U.S. Pat. No. 5,807,451, issued Sep. 15, 1998, or Miska, U.S. Pat. No. 4,288,483, issued Sep. 8, 1981.
Pile weatherstripping has conventionally been provided by piles which project upwardly into a brush, rather than are formed into a brush providing the pile seal upon insertion in the pile receiving slot. Even when strands are wound around a loop and cut into sections, the winding provides bush-like structure with bases or cores to facilitate holding the pile in the slot. See for example, the above cited patents and Metzler, U.S. Pat. Re. No. 30,359, issued Aug. 5, 1980.
The range of flexure of conventional pile weatherstripping may be limited when the sealing action is accompanied by the crushing of the pile. Such crushing mode operation can exert forces sufficient to bind the movable sealed unit, such as a sash of a window or door frame, which prevents opening of the window or door without more than desirable force. In other words, the stiff strands apply pressure on the sash and cause binding on the sides of the sash. The present invention provides a sash which can operate in a bending mode; providing sealing without significant crushing of the pile and enabling the pile to bend over a range, commensurate with the height of the pile, over the surface of the member through which the pile extends. The stiffness and height of the pile are therefore controllable. Moreover when barrier fins are used, the bending action also bends the fin rather than causes crenellation which detracts from the sealing action.
Pile weatherstrip provided by the invention may utilize a locking fin on the outside of the flat pile. The inside of the pile is defined by the parts, around the bend, formed when the flat pile is inserted in the slot, which parts face each other. With a locking fin, the force to insert the weatherstripping, preferably by rolling into the slot, is much less than the force to remove the weatherstripping.
In order to control compressive forces exerted by the pile in the crushing mode, the density of the pile (strands per given area) has been reduced, sacrificing the sealing action of the pile. Pile weatherstripping in accordance with the invention can be operated in the crushing mode if desired and without sacrificing the sealing action thereof.
Another advantage of the flat pile weatherstripping provided by the invention is that it is adapted to be assembled by welding, for example, with a bead (a filament) which extends along the inside of the pile. The use of a locking fin facilitates distribution of ultrasonic welding energy and avoids burning of the strands. Locking fins thus afford a further advantage when used in weatherstripping provided by the invention. The lateral spacing of the bent parts (tufts) of the weatherstrip is a function of the diameter of the bead and the width of the T-slot. The compressibility of the pile, even in the crushing mode, may be selectable in accordance with the diameter of the bead and without sacrificing the density and sealing effectivity of the pile. Selectability of bead diameter is still another feature of the invention.
Weatherstripping provided by the invention may readily be made by winding processes which maintain the strands under tension so as to pre-stress or bias the strands to return to straight condition, thus providing a pile which tends to lie flat. Winding processes for making flat pile are similar to those used in weaving and may be of the type described in U.S. Pat. No. 4,022,642, issued May 1977 to Abel, and U.S. Pat. No. 1,895,293, issued January 1933 to Morton.
Another advantage of the invention is to provide weatherstripping which is easy to store and may be wound flat around a reel for shipping or storage. Furthermore, the winding can be at higher density and without capturing significant air, and thus the amount of linear footage that can be stored on a standard reel is substantially increased over conventional weatherstripping. Still another advantage of the invention is that the pile may be formed into a slot which may be other than perpendicular to a flat surface of the member to be scaled. The slot may be disposed at an angle less than 90 degrees and even in to a corner of the member.
Briefly described, a pile weatherstrip in accordance with the invention forms a flexible seal projecting from the member to be sealed when received in a holding slot in the member. The slot may, as conventional, extend longitudinally of the member. The slot has a throat which defines steps along opposite edges of the throat internally of the slot. The slot may be a kerf where the throat is provided by teeth which define the edges. A plurality of strands are stacked in side-by-side relationship to provide a flat pile. The strands have resiliency tending to maintain them straight, that is, perpendicular to a longitudinal axis, about which the flat pile defined by the strands is bent. Upon insertion into the slot, the strands are bent inwardly, along the axis which divides the pile into separate parts. These parts are tensioned, because of the tension in the strands, to spring outwardly. Preferably, a locking fin on the outside of the flat pile, is located internally of the slot, and engages the edges at the throat as the locking, fin spring outwardly, so as to retain the weatherstripping in the slot. End portions of the parts of the strands extend outwardly from the slot and define the flexible pile seal.